#!/bin/sh
#
# ensure we never fallback from a signed to a unsigned repo
# 
# hash checks are done in 
# 
set -e

simulate_mitm_and_inject_evil_package()
{
    redatereleasefiles '+1 hour'
    rm -f "$APTARCHIVE/dists/unstable/InRelease" "$APTARCHIVE/dists/unstable/Release.gpg"
    inject_evil_package
}

inject_evil_package()
{
    cat > "$APTARCHIVE/dists/unstable/main/binary-i386/Packages" <<EOF
Package: evil
Installed-Size: 29
Maintainer: Joe Sixpack <joe@example.org>
Architecture: all
Version: 1.0
Filename: pool/evil_1.0_all.deb
Size: 1270
Description: an autogenerated evil package
EOF
    # avoid ims hit
    touch -d '+1hour' aptarchive/dists/unstable/main/binary-i386/Packages
    compressfile aptarchive/dists/unstable/main/binary-i386/Packages
}

assert_update_is_refused_and_last_good_state_used()
{
    testfailuremsg "E: The repository 'file:${APTARCHIVE} unstable Release' is no longer signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details." aptget update

    assert_repo_is_intact
}

assert_repo_is_intact()
{
    testsuccessequal "dpkg/now 1.16.2+fake all [installed,local]
foo/unstable 2.0 all" apt list -qq
    testsuccess aptget install -y -s foo
    testfailure aptget install -y evil
    testsuccess aptget source foo --print-uris

    LISTDIR=rootdir/var/lib/apt/lists
    testempty find "$LISTDIR" -name 'InRelease' -o -name 'Release.gpg'
}

setupaptarchive_with_lists_clean()
{
    setupaptarchive --no-update
    rm -rf rootdir/var/lib/apt/lists
}

test_from_inrelease_to_unsigned()
{
    export APT_DONT_SIGN='Release.gpg'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    simulate_mitm_and_inject_evil_package
    assert_update_is_refused_and_last_good_state_used
    testfileequal lists.before "$(listcurrentlistsdirectory)"
}

test_from_release_gpg_to_unsigned()
{
    export APT_DONT_SIGN='InRelease'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    simulate_mitm_and_inject_evil_package
    assert_update_is_refused_and_last_good_state_used
    testfileequal lists.before "$(listcurrentlistsdirectory)"
}

test_from_inrelease_to_unsigned_with_override()
{
    export APT_DONT_SIGN='Release.gpg'
    # setup archive with InRelease file
    setupaptarchive_with_lists_clean
    testsuccess aptget update

    # simulate moving to a unsigned but otherwise valid repo
    simulate_mitm_and_inject_evil_package
    generatereleasefiles '+2 hours'
    find "$APTARCHIVE" -name '*Packages*' -exec touch -d '+2 hours' {} \;

    # and ensure we can update to it (with enough force) 
    testfailure apt update
    testfailure aptget update
    testfailure aptget update --allow-insecure-repositories
    testfailure aptget update --no-allow-insecure-repositories
    sed -i 's#^deb\(-src\)\? #deb\1 [allow-downgrade-to-insecure=yes] #' rootdir/etc/apt/sources.list.d/*
    testfailure aptget update --no-allow-insecure-repositories
    testfailure apt update
    testwarning apt update --allow-insecure-repositories \
        -o Debug::pkgAcquire::Worker=1 -o Debug::pkgAcquire::Auth=1
    sed -i 's#^deb\(-src\)\? \[allow-downgrade-to-insecure=yes\] #deb\1 #' rootdir/etc/apt/sources.list.d/*
    # but that the individual packages are still considered untrusted
    testfailureequal "WARNING: The following packages cannot be authenticated!
  evil
E: There were unauthenticated packages and -y was used without --allow-unauthenticated" aptget install -qq -y evil
}

test_from_inrelease_to_norelease_with_override()
{
    # setup archive with InRelease file
    setupaptarchive_with_lists_clean
    testsuccess aptget update

    # simulate moving to a unsigned but otherwise valid repo
    simulate_mitm_and_inject_evil_package
    find "$APTARCHIVE" -name '*Release*' -delete
    find "$APTARCHIVE" -name '*Packages*' -exec touch -d '+2 hours' {} \;

    # and ensure we can update to it (with enough force) 
    testfailure aptget update
    testfailure aptget update --allow-insecure-repositories
    testwarning aptget update --allow-insecure-repositories \
        -o Acquire::AllowDowngradeToInsecureRepositories=1 -o Debug::pkgAcquire::Worker=1 -o Debug::pkgAcquire::Auth=1
    # but that the individual packages are still considered untrusted
    testfailureequal "WARNING: The following packages cannot be authenticated!
  evil
E: There were unauthenticated packages and -y was used without --allow-unauthenticated" aptget install -qq -y evil
}

test_cve_2012_0214()
{
    # see https://bugs.launchpad.net/ubuntu/+source/apt/+bug/947108
    #
    # it was possible to MITM the download so that InRelease/Release.gpg
    # are not delivered (404) and a altered Release file was send
    #
    # apt left the old InRelease file in /var/lib/apt/lists and downloaded
    # the unauthenticated Release file too giving the false impression that
    # Release was authenticated
    #
    # Note that this is pretty much impossible nowadays because:
    # a) InRelease is left as is, not split to InRelease/Release as it was 
    #    in the old days
    # b) we refuse to go from signed->unsigned
    #
    # Still worth having a regression test the simulates the condition

    export APT_DONT_SIGN='Release.gpg'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    # do what CVE-2012-0214 did
    rm -f "$APTARCHIVE/dists/unstable/InRelease" "$APTARCHIVE/dists/unstable/Release.gpg"
    inject_evil_package
    # build valid Release file
    aptftparchive -qq release ./aptarchive > aptarchive/dists/unstable/Release

    assert_update_is_refused_and_last_good_state_used
    testfileequal lists.before "$(listcurrentlistsdirectory)"

    # ensure there is no _Release file downloaded
    testfailure ls rootdir/var/lib/apt/lists/*_Release
}

test_subvert_inrelease()
{
    export APT_DONT_SIGN='Release.gpg'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    # replace InRelease with something else
    mv "$APTARCHIVE/dists/unstable/Release" "$APTARCHIVE/dists/unstable/InRelease"

    testfailuremsg "E: Failed to fetch file://${APTARCHIVE}/dists/unstable/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?)
E: The repository 'file:${APTARCHIVE} unstable InRelease' is no longer signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details." aptget update

    # ensure we keep the repo
    testfileequal lists.before "$(listcurrentlistsdirectory)"
    assert_repo_is_intact
}

test_inrelease_to_invalid_inrelease()
{
    export APT_DONT_SIGN='Release.gpg'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    # now remove InRelease and subvert Release do no longer verify
    sed -i 's/^Codename:.*/Codename: evil!/' "$APTARCHIVE/dists/unstable/InRelease"
    inject_evil_package

    testwarningequal "W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: file:${APTARCHIVE} unstable InRelease: The following signatures were invalid: BADSIG 5A90D141DBAC8DAE Joe Sixpack (APT Testcases Dummy) <joe@example.org>
W: Failed to fetch file:${APTARCHIVE}/dists/unstable/InRelease  The following signatures were invalid: BADSIG 5A90D141DBAC8DAE Joe Sixpack (APT Testcases Dummy) <joe@example.org>
W: Some index files failed to download. They have been ignored, or old ones used instead." aptget update -qq

    # ensure we keep the repo
    testfailure grep 'evil' rootdir/var/lib/apt/lists/*InRelease
    testfileequal lists.before "$(listcurrentlistsdirectory)"
    assert_repo_is_intact
}

test_release_gpg_to_invalid_release_release_gpg()
{
    export APT_DONT_SIGN='InRelease'
    setupaptarchive_with_lists_clean
    testsuccess aptget update
    listcurrentlistsdirectory > lists.before

    # now subvert Release do no longer verify
    echo "Some evil data" >> "$APTARCHIVE/dists/unstable/Release"
    inject_evil_package

    testwarningequal "W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: file:${APTARCHIVE} unstable Release: The following signatures were invalid: BADSIG 5A90D141DBAC8DAE Joe Sixpack (APT Testcases Dummy) <joe@example.org>
W: Failed to fetch file:${APTARCHIVE}/dists/unstable/Release.gpg  The following signatures were invalid: BADSIG 5A90D141DBAC8DAE Joe Sixpack (APT Testcases Dummy) <joe@example.org>
W: Some index files failed to download. They have been ignored, or old ones used instead." aptget update -qq

    testfailure grep 'evil' rootdir/var/lib/apt/lists/*Release
    testfileequal lists.before "$(listcurrentlistsdirectory)"
    assert_repo_is_intact
}


TESTDIR="$(readlink -f "$(dirname "$0")")"
. "$TESTDIR/framework"

setupenvironment
configarchitecture "i386"

# a "normal" package with source and binary
buildsimplenativepackage 'foo' 'all' '2.0'

# setup the archive and ensure we have a single package that installs fine
setupaptarchive
APTARCHIVE="$(readlink -f ./aptarchive)"
assert_repo_is_intact

# test the various cases where a repo may go from signed->unsigned
msgmsg "test_from_inrelease_to_unsigned"
test_from_inrelease_to_unsigned

msgmsg "test_from_release_gpg_to_unsigned"
test_from_release_gpg_to_unsigned

# ensure we do not regress on CVE-2012-0214
msgmsg "test_cve_2012_0214"
test_cve_2012_0214

# ensure InRelease can not be subverted
msgmsg "test_subvert_inrelease"
test_subvert_inrelease

# ensure we revert to last good state if InRelease does not verify
msgmsg "test_inrelease_to_invalid_inrelease"
test_inrelease_to_invalid_inrelease

# ensure we revert to last good state if Release/Release.gpg does not verify
msgmsg "test_release_gpg_to_invalid_release_release_gpg"
test_release_gpg_to_invalid_release_release_gpg

# ensure we can override the downgrade error
msgmsg "test_from_inrelease_to_unsigned_with_override"
test_from_inrelease_to_unsigned_with_override
msgmsg "test_from_inrelease_to_norelease_with_override"
test_from_inrelease_to_norelease_with_override
